DTC Troubleshooting: P1031 (183)
DTC P1031:
 Fuel Heater Circuit Malfunction
NOTE: Before you troubleshoot, record all freeze data and review the general troubleshooting information.
  1. Turn the ignition switch ON (II).
  1. Clear the DTC with the HDS.
  1. Do the FUEL HEATER ON/OFF in the INSPECTION MENU with the HDS.
  1. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P1031 indicated?
YES -
Go to Step 5 .
NO -
Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the fuel heater the fuel heater relay and the ECM.■
  1. Turn the ignition switch OFF.
  1. Check the No. 25 FUEL HEATER MONITOR (7.5 A) fuse in the under-hood fuse/relay box.
Is the fuse OK?
YES -
Go to Step 7 .
NO -
Replace the No. 25 FUEL HEATER MONITOR (7.5 A) fuse, then go to Step 18 .
  1. Remove the under-hood fuse/relay box.
  1. Check the fuel heater relay.
Is the fuel heater relay OK?
YES -
Go to Step 9 .
NO -
Replace the under-hood fuse/relay box, then go to Step 18 .
  1. Disconnect ECM connector No. 1 (96P).
  1. Disconnect the fuel heater 2P connector.
  1. Turn the ignition switch ON (II).
  1. Measure voltage between ECM connector No. 1 terminal No. 37 and body ground.
Is there battery voltage?
YES -
Repair short to power in the wire between the fuel heater relay and ECM connector No. 1 terminal No. 37, then go to Step 17 .
NO -
Go to Step 13 .